Method of and apparatus for rating time-pieces



(No Model.)

7 Sheets-Sheet 1. C. E. PMERY. METHOD OP AND APPARATUS POR RATING TIME PIECES.

No. 151,181l

Patented Ap1".28,1891.

we noms PETERS co., wom-uwe.. wAsmNs-rcu, n. c.

(No Model.) 7 Sheets-Sheet 2.

C. E. EMERY. METHOD OP AND APPARATUS PQR RATING'TIME PIECES.

Patented Apr. v28, 1891.

Wiwve s 7 Sheets-Sheet 3.

(No Model.)

C. E. EMERY. METHOD 0T AND APPARATUS POR RATING TIME PIECES.

. Patented Apr. 28, 1891.

unal/Infra111/111111/111/111//11//1/1//0/ Tus Noms Para cof. Pucwcvmno., wumncwuu, v c.

.7 Sheets-Sheet 4.

(No Model.)

C. E. EMBRY. METHOD OT'AND ATPARATUS TOR RATING TIME PIECES.

Patented Apr. 28; 1891 7 Sheets--Sheet 5.

(No Model.)

e. E. BMERY. l METHOD OP AND APPARATUS POR RATING TIME PIECES. No. 451,181.

Patented Apr. 28,1891.

TH: noms uns co., Now-uma., wAsmNa'mN, n. c.

(No Model) 1 7 Sheets-Sheet 6.

o. E. EMERY. V

METHOD 0F AND APPARATUS FOR RATING TIME PIECES.

PatentedApr. 28,1891.

TN: mams Pen-.ns co2, moro-uma., wxsmumon, n. c,

Zig. 50.

WIE/lemma,

(No Model.) 7 Sheets-Sheet. 7.

C. E. EMERY. METHOD 0F AND APPARATUS FOR RATING TIME PIECES.

4No. 451,18T. PatentedApr. 28,1891.

rn: cams vanas co., novo-umn., msnm-rau, n. r.4

Nrrnn raras nrnNT. rrrcn.

CHARLES E. EMERY, OF BROOKLYN, NEY YORK.

SPECIFICATION forming part of Letters Patent No. 451,181, dated April 28, 1891.

Application filed May 2, 1890. Serial No. 350,256. (No model.)

To all whom, t may concern:

Be it known that I, CHARLES E. EMERY, of Brooklyn, Kings county, New York, (office New York city,) have invented certain new and 'useful Improvements in the Method of and Apparatus Used for Rating lVatches and Clocks; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, making part of this speciication.

Section l. The principal object ot the invention is to produce a timing` or time-comparingapparatus so delicate in its action that it may be determined in a few minutes whether a balance or pendulum is running faster or slower than a standard, even if the variation in rate be only a few seconds a day, so that changes necessary to adjust the rate may be made promptly, the comparison repeated at once and adjustments again made, as may be necessary, all as part of one continuous operation without waiting to run the watches or clocks at first for hours and finally al day at least between each adjust- 1nent,`as is required at present.

Section 2. A further object of theinvention is to provide means whereby in one apparatus the watches and clocks may be promptly compared under diierent temperatures and pressures and the former in dierent positions and the more delicate corrections due to these conditions be also made at once, requiring only a sufficient number of movements actually undergoing test to give time between the operations on each for the metal ot the balances to assume the tension and shape due to the change of condition.

Section 3. To secure the desired delicacy of the time-comparing apparatus, which we will term a comparator,7 it is necessary to be able to observe promptly the slightest variation in the motion ofthe balance or pendulum undergoing test from that of the standard with which it is being compared. The point to be observed on the balance or pendulum undergoing test will be called the objectpoint and the point on the moving standard with which the motionv of the obj ect-point is to be compared will be called the compas ing-point. These points jointly will be called points of reterence, and are preferably located on the rims ot the standard balance or equivalent and of the balance undergoing test, so that the aXes of both balances when at rest and thepoints ot reference are in the same plane called the plane of reference. Similarly the points of reference of pendulums would be fixed when they are hanging vertically opposite each other, so that the plane of reference will run through the points of suspension and points of reference. In either case the points of reference p during operation cross the plane of reference when the balances or pendulu ms are moving at their highest velocity.

Section 4. The inventions embodied herein provide means for optically viewing` a slowlymoving or stationary image of the points of reference when the latter are actually moving at their highest velocity, whereby any change of the relative positions of the two may be detected at once as readily nearly as if such points were actually moving in relation to each other with only their difference of velocity. This is accomplished somewhat on the principle used in equatorial telescopes to keep the axis of the telescope practically lixed on a given star, notwithstanding the motion of the earth. As the surface ot the earth moves from west to east, the telescope is caused to swing around a polar axis from east to west with practically the same angular velocity. The same details and method of operation would evidently be applicable if the star were moving rapidly and the earth were stationary. To apply this principle in viewing minute objects, like the points of reference referred to, the observations are made through a mirror which receives such motion that the angle of incidence of its surface in relation to such points when practically coincident and the angle of reflection from such surface to the eye or line of sight will be the same or approximately the same, in which case the image of the moving points will appear stationary or moving so slowly that the relative motion of the two can be accurately determined. The mirror may be swung on an axis independent ot that of either balance, when preferably the line of sight would be in the plane of the motion of IOO the points, or the mirror may be carried by one of the balances, when preferably the line of sight would be in the direction of the axis. The latter mode of operation will lirst be described in full, and may be illustated by supposing an observer situated at the center of the platform of a curriculum in rapid revolution and looking` radially outward through an opera-glass. The view of objects off the platform would be indistinct on account of the relative velocity, although the observer was changing angle slowly; but if the glass were directed at the uplifted hands of two children riding side by side at the outer edge of the platform, where the actual motion would be rapid, the slightest movement of the hand of one in relation to that of the other could be observed because the optical axis of the glass would be moving at practically the same velocity as the children, and the difference of movement of the hands could as readily be distinguished as if no other movement were taking place. If the observer should put an inclined mirror in his chair at the center and then lie out on the stationary roof of the structure and look through his opera-glass downward in the mirror through a central opening'in the roof, he would still see the image of the hands of the children and could watch their relative movements as well as if actually on the platform. Any particular point-for instance, the linger-nail of one linger of one ofthe childrencould be brought in focus, when the image of it would appear absolutely still to the observer, although the point itself was moving rapidly through space. All the parts surrounding the central point in exact focus would appear in the image to revolve around the image of the point, but so slowly that the relative movements of parts near could be watched as closely as if there were no other motion than such relative movement. Objects off the platform would appear confused, as before; but if another platform were revolving at the same speed and with adjacent sides in the same direction alongside it objects on that would appear stationary at the moment of passing and the relative change of position of points on the two platforms which came nearly opposite at the moment of passing could be observed. In the same way the motion of the points of reference on two watch-balances may be observed at the time they are moving at nearly the same speed past the plane of reference by looking downward at an image of the same in an inclined mirror over the axis of one of the balances and moving with it. This principle is applied in a number of ways and with balances in a number of positions. Combinations of lenses and mirrors are provided, so that the slightest variation in the position of the points of reference when crossing the plane of reference may be detected, and by observations of successive vibrations it may be seen whether the object-point has moved ahead or has fallen hable with the complete form.

behind the comparing-point. The delicacy of this method of operation is phenomenal. If the watch beat five times per second and the balance move through three hundred and sixty degrees at each beat, the main velocity will be tive by three hundred and sixty degrees, or eighteen hundred degrees per second; but since the velocity is zero at the close of each vibration the maximum velocity, or that at the time the points of reference pass the plane of reference, will be about three thousand degrees per second, and if an ordinary observer can surely see a variation of ten degrees in the position of the points of reference this will correspond to an error of one three-hundredth of a second. If therefore a variation of ten degrees be discovered in one second, since there are eighty-six thousand four hundred seconds in a day, this error would correspond to (eighty-six thousand four hundred divided by three hundred equals) two hundred and eighty-eight seconds or 4.8 minutes per day; but if it required one minute to discover the same variation of ten degrees it would indicate an error of only oue-sixtieth of two hundred and eighty-eightv seconds or 4.8 seconds per day, or, if discovered in two minutes, to 2.4i seconds per day. Close observers would be able to discover a variation of tive degrees, and would therefore be able to detect an error ot' 2.4 seconds a day in a. single minute. Such observations are well within the requirements for temperature and position adjustments. In the more delicate operations the balances would require to be in place in the movements, so as to secure and retain very high velocities. f A similar method of observation can be applied to balances when vibrated by hand; but more time will be required for very delicate adjustments, though the length of the spring can be fixed in a very short time within such limits that the exact adjustment can be obtained with the regulator;

Section 5. The inspection of the points of reference when in motion is accomplished optically by a combination of lenses and mirrors, which, with the movement to be tested and the standard, are in the complete form of apparatus preferably inclosed in a small case, through which air of different temperatures may be forced in making temperature adjustments, and whichis so connected with the supporting and operating mechanism that it can be turned in different positions to test the movement for position. These tests are preferably made with the balance connected in the movement, which latteris mounted in a box adapted to form a drawer, which can ordinarily be kept in one of a series of drawer-cases, and there maintained at any desired temperature between the periods of comparison with the standard. In the specications various forms of mechanism are shown, some adapted for the complete adjustment of a watch, others to accomplish parts of the results obtain- In some cases IOO IIO

a vibrating standard in the form of a balance resembling that to be tested is used, and in others a revolving standard is employed in which the point of comparison comes into view for every double beat of the balance to be tested. In all cases provision is made to cut off the view of the points of reference during the portion of the double beat in which motion is in a wrong direction. Adaptations of the same apparatus are applicable in rating pendulums. The invention involves a great number of details, which can best be set forth in connection with the description.

Section 6. In the drawings, Figure 1, Sheet' 1,is a plan View, part-ly in section, of a comparator-case with a movement secured in a small drawer in such case. Fig. 2, Sheet 1, is a longitudinal section through the case and drawer and through portions of the comparator mechanism. Fig; 3, Sheet 2, is an elevation, on a smaller scale, of a complete appararat-us embodying an external side view of the case shown in the previous figures. Fig. 4, Sheet 2, is a similar elevation of a modification of the parts shown in Fig. 3, with a dierent form of apparatus for securing angular adjustment and adapted for the use of a series of comparators operated by the same mechanism. Fig. 5, Sheet 2, is a view, on a still smaller scale, showing the general arrangement of the elements when such a series ot' comparators is used. Fig. 5, Sheet 3, is a plan view, partly in section, of another form of comparator-case in which an objectmirror revolves entirely around a watch-movement; and Fig. 7, Sheet 3, is a vertical central section through same with side view of some details. Fig. 8, Sheet 4, shows a general arrangement, on a small scale, of apparatus for circulating and regulating the temperature of the air used in making the comparisons for temperature adjustments. Fig. 9, Sheet 4, shows apparatus for automatically regulating the-temperature. Fig. 10, Sheet 3,-is a view of an apparat-us for varying the angularvelocity of a driven shaft in dierent parts of a revolution, to be used in connection with the revolving comparator above referred to. Fig. 1l, Sheet 3, is a vertical elevation of the slotted dish shown in Fig. 10. Fig. 12, Sheet 3, is a vertical elevation, partly in section, of a vibrating apparatus with vibrating standard balance, showing one application of the principles of the invenqtion to simple apparatus for ordinary vibrating purposes. Figs. 13 and 14, Sheet 5, are respectively a vertical elevation, partly in section, and a plan view of a modified apparatus for the purpose last above stated. Fig. 15, Sheet 5, is a vertical elevation, partly in section, of a modified apparatus, also for the same purpose; Fig. 16, Sheet 5, a transverse View, looking from the left, of the principal supporting-frame of the apparatus, shown in Fig. 15. Fig. 17, Sheet 5, is avertical elevation, partly in section, of a fragment of a modification of the apparatus shown in Fig. 15. Fig. 1S, Sheet 5,is a similar View of a fragment of a modiication'of the apparatus shown in Fig. 13. Fig. 19, Sheet 4, is a diagramv plan view; and Fig. 20, Sheet 4, an elevation, partly in section, of still another modified form of apparatus for the purpose set forth in the description ot Fig. 12. Fig. 21, Sheet 4, is a plan view of the balance-bridge of the same. Fig. 22, Sheet 4,is a plan view; and Fig. 23, Sheet 4, a vertical elevation, partly in section, of the principal parts ot' a modified apparatus tor the purpose set forth in the description of Fig. 12. Fig. 24, VSheet 4, is an elevation, partly in section, of a modified apparatus for the same purpose. Fig. 25, Sheet 1, is aplan view, and Figs. 26 and 27, Sheet 1, are respectively side and front elevations, partly in section, of a vibrating apparatus for comparing balances with a cut-off operated by a pendulum. Fig. 28, Sheet 6, is avertical elevation of a comparator-case for pendulums, combined with means for operating a cut-off. Fig. 29 is a side elevation, and Fig. 30, Sheet 6, a plan view of the same. Figs. 31 and 32, Sheet 6, are respectively front and side elevations of modifications of the cut-off apparatus shown in Figs. 28 and 29. Fig. 33, Sheet 6', is a diagram illustrating a method of operating cut-off disks and comparing-points from a prime mover. Fig. 34, Sheet 1, shows devices for the same purpose as the above in connection with a comparing-chamber and with apparatus for transmitting regular motion from a prime mover; Fig. 35, Sheet 7, an outline view, with parts in section, of apparatus for regulating the air-pressure.` Fig. 36, Sheet- 7, is a diagram showing the changes necessary in the angle of a vibrating objectmirror to keep in view objects moving in a plane at right angles to its face. Fig. 37, Sheet 7, is a fragmentary front view, partly in section, and Fig. 3S, Sheet 7, a side view, partly in section and partly in outline, showing a combination of parts adapted for the use of a vibrating object-mirror not carried by a balance.

Section 7. The following are the names and designating letters of some ot' the principal details of the apparatus, viz: a comparingpoint a, an object-point c, a comparator-disk F, a standard balance t, a balance for comparison u, a standard pendulum W, apendulum for comparison X, a cut-off V, (section 21,) a mirror at the center m, an eye-piece L, a lens therein e, a drawer to contain a watchmovement for comparison D and D', a comparator-case for a watch-movement E and E', a watch-mm-*ement as a whole B, a comparing chamber. for clocks U, equalizing airchambers O O Ocases for containing watchmovement drawers K K K2, and pipes on comparator-cases for circulating air 7o. In addition to the above the following terms land designations will be used to express mechanical movements as a whole adapted for a particular purpose, as described in sections referred to, viz: a regulated prime moverR,

IOO

IIO

(Sec. 16;) an angular adjusting apparatus S, (Sec. 10;) apparatus for varying the angular velocity T, (See. 18.)

Section 8. In Figs. 1 and 2, Sheet 1, u represents a watch-balance mounted, preferably, in connection with the entire movement B, of which the plates b ZJ are shown and are secured by clamps or other means in a iixture c, which in turn is fastened securely in the bottom of a drawer, (designated as a whole D,) of which d is the bottom plate, d the end plate, and d2 the handle. The drawer D moves from left to right upon the bottom between the sides and under ledges in a comparatorcase (designated as a whole E.) F is a comparator-disk carried by a spindle f, the disk being provided at a point on its circumference Wit-h a comparing-point a and carrying at its center an inclined mirror m. L is an eyepiece, and e a magnifying-lens, with axis arranged in the line of the axis of the spindle f and of the comparator-disk F. The objectpoint in this case is represented by the screw n, which, as shown, stands opposite the comparing-point a when both are at rest and in a vertical plane passing through the axis of the balance and of comparator-disk The comparatordisk F, carrying comparing-point a, is to be revolved once for each double vibration of the balance and the points of reference are made to pass the plane of reference at substantially the same velocity either by adjusting the position of the comparingpoint a in relation to the center of the comparator-disk F or by the use of an apparatus T for varying the angular velocity of the disk. (Sec. 1S.) If, under such circumstances, the balance u and the comparator-disk F be put in motion, the image of the comparing-point a (seen through lens ein eye-piece L) will,when in proper focus, appear stationary, though the comparing-point itself is moving at avery high velocity, and momentarily during each double beat the object-point c will also appear stationary or moving at such reduced speed as to be seen. In the particular form of apparatus shown in this figure such object-point c Will approach and recede from the comparing-point a, so as to change its relative angular velocity, and will thereforeappear once during each double vibration to rapidly approach the comparing-point a, dwell slightly, and then as rapidly recede in a cusp-shaped path like that shown by a persons foot when viewed from below in walking on a grating; but an observer can detect during succeeding vibrations Whether the points of the cusp traced by object point n coincide with or gradually move to the right or to the left compared with comparing-point a. For instance, if the comparator-disk F be moving regularly to the left and object-point o appear gradually to move to the left of comparing-point a the balance will be running fast, and if observed point n should appear to be gradually moving to the right with reference to comparing-point a the balance Will be running slowly, and vice versa. These variations can, as previously explained, (Sec. 4,) be promptly detected and adjustments made to vary the rate of the watch until the balance keeps time with the standard within a predetermined limit of error.

Section D. The illumination of the comparing-point a and object-point Q; is secured by a light in the direction o, preferably provided with a condensing mirror or lens, or both, directing the rays upon a condensingmirror 0', from which the rays are reflected and condensed upon the points of reference d and `v when they pass the plane of reference. Any other system of condensing lenses or mirrors or other means of illumination may be adopted. To prevent the light from illuminating-mirror o from falling upon the mirror m when the latter is turned toward the former, a disk j is placed just above the plane of revolution of mirror `m, but with a sector removed on the lines j j', Fig. 1, corresponding to the angle in which it is desired to see the points of reference a and n.

Section 10. The hollow spindle f of comparing-disk F is operated by a spindle g, secured to a Wheel G through a central rod h, provided with a driven pin h', running in a longitudinal slot in the driving-spindle g, and a driving-pin h2, engaging with a spiral slot f in the spindle f. The Wheel Gr is operated by a pinion I through a spur-gear on its edges when in the position shown in full lines, and through an attached bevel-gear, when, as vhereinafter described, (Sec. 11,) the whole apparatus is revolved through ninety degrees, so that the wheel G takes the position shown by the dotted lines G. Il is a lever arranged with pins and rollers to engage between collars hg h3 on rod 7L, and by moving the rod L- longitudinally with the lever between the positions I'I II the pin h2 will, by its operation in the spiral groove f', change the angular position of the spindlef of the comparator-disk F relatively to operatingwheel G, and with it the angular position of the comparing-point a, and evidently this change of angle may be made either when the parts are stationary or when the comparator-wheel F is in motion. In operation the pinion I would be given a motion from a regulated prime mover R, (Sec. 16,) such as would impart by the means shown to the disk F one revolution for each double vibration of a standard-balance. If, however, the comparing -point d in starting an observation pass the plane of reference at a different time than the object-point o, the disk F may While in motion be angularly adjusted by operating lever Il, as described, so thatboth points of reference will pass the plane of reference at the same time when the lever II, beingleft in that position and held bya spring or catch the comparison can at once proceed, as above described. (Sec. 8.) In Fig. 4t, Sheet 2, is shown a modification of the above apparatus. In this case the spindle f of the comparator disk is IOO ITO

made conti nuous with the spindle ot the wheel G, which, as before, receives mot-ion from a pinion Land the lower end ofthe spindle 202 of pinionlreceives motion from a bevel-gear thereon, which in turn is moved through another bevel-gear 37 at the left by abevel-gear 3S, carried on a spindle 203, which may be connected with spindle l27 of the electric motor, Fig. 3, Sheet 2, or, as shown in Fig. 4, with a bevel-gear 39, operated by any regulated prime mover. The bevel-gear 3S at the side runs loosely on a pin provided with a handle 200 at the left and secured at the right in a central cross 201. This cross is pivoted to and can freely revolve with handle 200 and bevel-gear 37 upon the ends of the upper and lower spindles 202 and 203, the bevel-gear 37 remaining in all` positions in mesh with the bevel-gears 3G and 38. rlhe handle 200 can be secured bya set-screw 204 upon a stationary arc 205. This are is in this case a complete circle, which is secured at the right in jaws attached to frame C', the-circle being shown in section at the left in the shank ot handle 200 and at the right in the jaws on the frame. The parallel lines show the continuation of the same circle beyond the section. By means of this arrangement, (marked asa whole S,) and which in this form will be recognized as a modilication of the familiarjack in-a-hox, the angular position of any point on gear 36 may be changed in relation to that of any point on driving-gear 38 by simply` swinging the handle 200 around on the central spindles 2 2 and 203 as far as practicable without interfering with the frame C, which action is evident it we suppose gear 3S to be held still and the handle 200 moved, when of course it will through gear 3S revolve the gear 3 6, and if all the gears are in motion an additional movement will be transmitted by handle 200, as well as if 3S were at rest. The change of the angular position of the bevelgear 3G in relation to the driving bevel-gear 38 will also be transmitted through pinion l to wheel Gr, driving the comparator-disk F, and by properly proportioning the gearwheels the comparator-disk F may be changed in angle through an entire revolution by operating the handle 200, though this would require that t-he pinion I be relatively larger in relation to wheel G than shown in this, particular view. This apparatus, as well as that operated `by the lever l-l in Fig. 2, Sheet l, (Sec. 10,) will be referred to herein as angular adjusting apparatus (designated as a whole S) and embodied as an element in several combinations.

Section 11.*The customary position of the comparator-ease E is shown in Fig. 8, Sheet 2, in which the rate of the balance would be tested with the movement on the Hat with the face or bezel down, as shown in Fig. 2, Sheet l. To test the rate on the tlat bezel up, it is simply necessary in this particular apparatus to withdraw the drawer D and turn it over, as the parts are so proportioned that the object-point 'U will be at the center of the drawer in either flat position ot the movement. To provide for testing in vertical positions, the case E, as shown in Fig. 2, Sheet l, is secured to a spindle t', which swivels in an eye in the end of a curved supporting-arm J, which, as shown in Fig. 3, Sheet 2, swings through an arc of ninety degrees in corresponding curved brackets in the top ot a frame C, provided with screws or other means to secure such curved arm J in either extreme position. In the position shown the spur-teeth on wheels I and Gare in gear; but when the arm J is swung around its center (at the junction of the pitch-circles of the spur and bevel gears) through an are of ninety degrees the bevel-gear teeth on pinion I engage with those on G' in the position of the dotted lines, the spindle t', supporting comparator-case E, becomes horizontal, and the spindle of the case may be turned in its bearing in the boss on the end of curved arm J, so that the position ot' the movement Will correspond with pendent up or down or right or left, the customary positions used in testing watches in vertical positions, and comparison made in either position without other adjustments except as to the location of the lamp for illumination, which must be adj usted for each position unless hung on the apparatus or in the form of a gas-jet or electric light with connecting iiexible pipes or wires. The provisions for circulating air, hereinafter described, can readily be adapted to all the changes of position.

IOO

Section l2, To provide for temperature adjustments air-nozzles 7c 7s are provided on the comparator-case E, in one otwhieh air, either hot, cold, or of medium temperature, may be blown through a conductinghose and pass out ot' the other,either through a conductinghose or into the room. Such an opening-for instance 7g2-may be in the handle d2 of the drawerD. In some cases, however, it is better not lo blow the air directly on the movement, but rather to produce and maintain the desired temperature by conduction through the metal of the drawer. For delicate movements the drawers may be made practically airtight and the balances viewed through glass, or in any case the case and seasoning-chambers may have hollow walls, between which fluid of any kind at a regulated temperature may be circulated to produce and maintain the desired temperature in the case and chamber. In adjusting the temperature it is proposed to maintain the movement at the .desired tem peratu re by circulating air of that temperature through the case E, when by observing the rates at two'extreme temperatures and any intermediate temperature desired the balance may be adjusted to correspond and tested again and again until made satisfactory. In practice it is proposed to erect near the apparatus three or more cases of drawers K, K', and K2, Fig. S,Sheet ,provided with drawer-openings of proper size to IOS ITO

' receiver drawer D, Fig. 1, Sheet 1, and to proA vide a sufficient number of drawers to entirely till the openings, also one spare one to contain the movement actually undergoing test. The cases of drawers are to be maintained at the different temperatures it is desired to employ-for instance, severally at 40", and 100O Fahrenheit. In Fig. 8, Sheet 4, M and M represent pumps or fan-blowers, one M drawing air over ice in a chamber-N through an inlet N4, the other M drawing air over a stove or heating-coil in a chamber l" through an inlet N3. rlhe outlets of the blowers are connected by suitable pipes and branches provided with valves n n with equalizing-chambers O O O2, which are severally connected by discharge-pipes p p p2 with the eases of drawers K K K2, and such cases are provided with outlet-valves q q q2. In operation cold air discharged by the blower M and hot air discharged by the blower M can by regulating the valves n n be mixed in any desired proportion in the right-hand compartments of the chambers O O O2 and be passed through screens or deiecting-plates to the main portions of the chambers, and from there be conveyed through the pipes p p p2 to the several cases of drawers K K K2. It is proposed to make the partitions between the drawers of cases in skeleton form, so that air blown in the cases can circulate over the entire surfaces of the drawers and finally escape by the outlets q q q2. For instance, O may be the hot room connected to case K and-sufficient hot air admitted to maintain both at a temperature of Similarly room O and case of drawers K can by properly mixing the air be kept at a temperature of 70", and room O2 and case of drawers K2 can by supplying a sufficient quantity of cold air be maintained at a temperature of 40. The hot air discharged at Q or cold air at q2 may in turn be conducted through a hose to the inlet it of the drawer E, Figs. l and 2, Sheet l, and return from outlet 7c of such drawer through a hose to the suction of the proper blower to prevent waste of heat or ice, or the return may be omitted and the circulating air be allowed to escape into the room through one of the branches 7c on comparator-case E. This case may receive air at an intermediate temperature of, say, 70 by connecting the same with outlet q or to any point on the pipe p leading from chamber O. Evidently, also, the desired temperature of comparator-case E may be obtained by direct connection to such one of the rooms O O O2 as is maintained at that temperature or to any of the pipes or connections leading thererefroin Section 13. The temperature of the air circulated through case E, Fig. 1, may be ascertained by inspecting a thermometer Z of any kind inserted in such case. To prevent discomfort in handling the comparator-box E,

, Fig. 1, Sheet 1, Fig. 3, Sheet 2, and to prevent posurc to the air, such box or any of the apparatus desired may bc covered with nonconducting material-for instance, in the space inclosed by the dotted lines surrounding box E in Fig. 3, Sheet 2.

Section lli. The temperatures may be maintained at the desired'point in the chambers O O O2 by automaticapparatus of 'customary form-such, forinstance,asis used in hatching devices. One method of doing this is shown in Fig. 9, Sheet 4, in which n4 represents one of the valves n n. A simple' butterfly-valve n3 is provided in the same pipe, and may be operated through an external arm by a crank on a shaft 20, which is given a tendency to revolve at the top from right to left by any motive force-for instance, the weight 24, shown connected to a drum on shaft 20. An arm 2l on this shaft is detained in the position shown by the armature 22 of an 'electric magnet 23, so that in the position shown the valve n3 is closed. 2-t represents a bimetallic plate or the end of the curved tube (filled with fluid) ofa metallic thermometer orany equivalent device in which motion is caused by change of temperature, such device being distinguished herein in general as a thermometer or bimetallic thermometer, though no scale is required if adjustment bemade with an ordinary thermometer. In the arrangement shown 2t moves in one direction for heat and in the other for cold. In one case, through the electric connections indicated, it closes an electric circuit to move the armature of electro-magnet 23, thus releasing arm 2l and allowing shaft 2O to revolve half a revolution until arm 21 thereon is detained bythe armature 26 of an electro-magnet 25, and thereby opening valve n3, and in the other case closing an electric circuit to electro-magnet 25 and causing armature 26 to release arm 21 and permit the motive force to close valve n3 again. By placing a bimetallic thermometer 21 in each of the equalizing-chambers O O 02a number of combinations maybe made to adjust the temperature. of each as desired. For instance, in the hot-chamber O the valve n, admitting cold air, may be nearly closed, and the valve n', admitting hot air to that chamber, be operated by apparatus similar to that described, governed by a bimetallic thermometer. A similar arrangementwould answer alsofor the equalizing-chamber O for the intermediate temperature; but evidently this temperature can be-maintained in summer, when the temperature is higher than 70o, by simply admitting cold air through a valve n under the control of a thermometer to keep the temperature down, when by placing the ice-chamber well above t-he point where the cold air is to be delivered such air will fall by gravity and circulate throughout the apparatus without a blower. In winter, when the normal `temperature is lower than that desired, the temperature can be maintained by simply admitting hot air under the control` of a thermometer through a Valve IOO IIO

n to keep, the temperature up, and it the heating devices are sufticientl y below the point where the hot air is to be delivered it will circulate without a blower. In eithei` case the air can be drawn through the apparatus by a heated chimney. Regulation of heat may also be made by shutting off a gasjet or closing the damper of a turnaceheab ing the air to be circulated. Similar methods of operation may be employed when the out-door temperature available is extreme for either of the other eqnalizing-chambers. Ordinarily to maintain'the lowtemperature in chamber O2 it would be found most convenient to admit a small quantity of warm air by regulating the valve n by hand and then operating the valve n, admitt-ing cold air through apparatus governed by a thermometer in the chamber coupled and arranged so that as the temperature rises cold air will be 'admit-ted and as il falls will be excluded. In other cases evidently two bimetallic thermometers may be used in each chamber, one connected to the hot-air inlet and arranged with suitable apparatus to admit hot air when the temperature falls below a certain point, the other thermometer arranged to govern the cold-air inlet and to admit cold air when the temperature rises above a certain point, and if the two thermometers are set with a slight diierence the temperature willbe m aintained at some mean point. The arrangement of equalizing-chambers O O O2 would be used also in connection with the testing of clocks for temperature, the pipes p p p2 being led to cases or rooms in which the clocks are located, as described hereinafter. The general arrangement here-in described for circulating air at a regulated temperature through comparing-chambers or other fluid ata regulated temperature through hollow casings surrounding such comparingchamber, though in detail very similar to apparatus used for heating and cooling rooms for otherV purposes, introduces, when applied to the regulation of clocks and watches, as described, a novel systeln of great advantage. Heretofore watch-movements have been put alternately in hot and cold chambers, trom which such watch-movements were necessarily removed to the work-benches of the operatives or adjusters in various parts of the building, or at every point where watches were adjusted furnaces and refrigerators were necessarily located. "With this arrangement there need be but one general arrangement for heating, and in connection therewith apparatus for refrigerating the circulating fluid, all of which can be located in or near the room supplying the power and be attended to as part of the general apparatus, like the engine, the heating apparatus, the electric-light apparatus, tbc., and from such apparatus for circulating fluid at a regulated temperature pipes be conducted to any part of the building where it is desired that testing operations be conducted,and branehesbe led directly to the work-bench of each operator on this class ot workv-for instance, to each comparator ot a series shown in fragmentary view in Fig. 5, Sheet 2, and a more detailed View of one of which is shown in Fig. 3 on same sheet.

Section l5. In operation all the drawers would be in place in the several cases K K K2 and one spare one be provided, so that if adjustments of movements running in the cold were being made in a particular comparator the drawer removed from the com parator-case E would be putin place ot` one removed from the drawer-case K2, which latter would be put in the comparator-case and the movement tested. The comparator-case would at that time be connected with the case ot drawers from which the movements were being taken. This operation would be repeated for each temperature desired and adjustments made between the trials. If movements were sent away for adj ustments, necessarilyspare draw! ers or Stoppers would be putin place of those removed from the drawer-case.

Section 16. In thelowerpartof Fig. 3, Sheet 2, is represented an electric motor for operating the comparator-disk through the gears I and G previously described. The spindle of the pinion I runs through along-bearing connected rigidly to the upper part of frame C, and such spindle connects in a yoke 2G with a hollow governor-spindle 27, provided with a lower bearing in the cross-barot the frame. The yoke 26 is secured to spindle 27 and carries goi-ernor-arms 2S 2S, provided with short arms turned inward and connecting with a sliding sleeve 29, which sleeve,.through apin moving in a slot in spindle 27, connects to a regulating-spindle 75, extending through the governor-spindle 27 and below the bottom of the same and bearing upon the short end of a lever 29, which at the other end is provided with a metallic point to open and close an electric circuit. 31 3l are fixed electricmagnets, and 32 electric magnets revolving with spindle 27. 33 are brushesinsulated from the frame, with their free ends bearing on a commutator Si on spindle 27, arranged in customary ways to make and break the current passing through the revolving magnets The current from the electric battery 7 G passes through the coils of fixed electro-magnets 3l, thence through the lett-hand brush 33 to the comm utator 34, thence through the coils of the revolving electro-magnets 32, and out upon the brush 33 at the right to the point 30 on lever 29,and the operation is such that when the speed of the apparatus slacks the balls 28 2S of the governor will fall toward the center, lifting the governor-spindle 2S, so that the point 30 will be depressed and come in contact with fixed point 35 and close the circuit, when the electric engine will increase its speed until the balls 2S again move out and break the circuit at 30. The height of the point is made adjustable to permit slight variations of speed by varying the height ot the balls in relation to the points IOO IIO

of suspension. In the lower part of Fig. 3l, Sheet l, is shown an apparatus to be connected to a prime motor and used as a substitute for the electric motor shown in Figs. Sand 5, Sheet 2. Q is an inclosure for the governing apparatus corresponding to that similarly designated in Fig. 5. In Fig. 3l there is, as in Fig. 3, a governor with balls 2S, mounted in a yoke 2G, secured to a hollow spindle 27. The balls are provided with arms turned inwardly to operate acentral rod ors pindie 75, and the yoke 26 is connected to a shaft 7(3,which may be connected to any apparatus it is desired to operate-for instance, that shown in Fig. 34 or the spindle of pinion I in Fig. 3. In Fig.- Sl the spindle 27 is continued downward and arranged to turn freelyinside a sleeve 80, secured to a bevel-gear 8l. The sleeve 8O of gear Sl revolves in a bearing in a frame 79. The bevel-gear Sl is kept in motion at a speed which should at all times slightly exceed that to be given the governorballs 2S by a prime motor of any kind from which motion is to be transmitted in any ine-- chanical way-for instance, through a bevelgear 82. A disk 83 is 'carried by adjustingnuts 84 on central spindle 75, and is by a splined or square rod and hole arranged so as to turn therewith and yet permit longitudinal motion from the adjusting-nuts Sl. The upper part of spindle carries a driving-pin 7S, running in a slot in the hollow spindle 27 of the governor. In operation, when the speed of the governor is reduced the balls fall, pulling up the central spindle 75 and bringing disk 83 in contact with the under face of the bevel-gear 8l,which imparts a certain degree of motion by friction to the disk, spindle, and governor until the latter is brought up to speed or a trifle higher, when by the expansion of the balls 28 the disk 83 is released from contact with wheel 8l. In practice the balls will generally maintain a position so that the pressure of the disk S3 on bevel-wheel Sl will be just sufficient to drive the governor to speed. The shaft 7G, operated by the governor, may carry vanes 77 to act on the air and produce a slight resistance to steady the apparatus, and, if desired, a ily-wheel like 44e, Fig. 5, Sheet 2, may also be used. Either form of apparatus above described will be found convenient for obtaining motion at a regulated speed, though any other regulated prime mover-such as a steam-engine with a delicate governor-may be employed. Such an `apparatus is referred to in general herein as aregulated prime mover, and designated as a whole R.

Section 17. Fig. et, Sheet 2, also shows a part of a modification of the driving apparatus of a revolving comparator, designed to operate several machines from the same prime motor. The wheel 39 may connect to pinion I and comparator-disk F either through the jack-in-the-box arrangement shown in Fig. 4, or evidently its spindle 203 may be connected directly tothe spindle of the pinion I in Fig. 3, where the angular adjustment is differently provided for. As shown in Fig. 4, the bevel-gear 39 is operated by a gear 40 on a shaft. 4l, corresponding to the shaft of the same number in Fig. 5, which, as shown, operates a number of machines, of which fragmentary views are shown. The shaft 4l, through bevel-gears #l2 and 43, is operated by a vertical shaft carrying a governor regulating any form of prime motor for instance, the electro-magnetic engine shown in Fig. ett is a fly-wheel to assist in keeping the speed uniform. The governor apparatus, in dependent of the type of prime mover, is preferably arranged in a separate room Q kept at uniform temperature-forinstance, in the basement of a building, or provided with connecting-pipes l5 4:5, connected with the apparatus for circulatingair. (Shown in Fig. S,Sheet 4.) In this way a series of comparator-disks may be operated simultaneously at the desired speed from a prime mover, the governor of which is adjusted for temperature by running in air of a uniform temperature. A uniform air-pressure may, if desired, also be maintained by connecting the chamber Q with apparatus for securing the same. (Sec. 24.)

Section 1S. The maximum velocity of an obj ect-point on a balance necessarily varies with the amplitude of vibration, for the reason that long and short ,arcs are made in the same time. If the balance und ergoing test be compared with another balance with the same amplitude of vibration, the velocities of the points of reference across the plane of reference will be thel same, whereas when a revolving comparator is used the velocity of the comparing -point, without special provision to the contrary, will be constant independent IOO of the amplitude of vibration and maximum velocity of the balance which is being compared with it. To overcome this di'iculty, means are provided to vary the angular velocity of the comparing-point as it passes the plane of reference. Such point must necessarily make an entire revolution in the time of the double beat of astandard balance; but its angular velocity may vary in different portions of its revolution. This can be accomplished by placing anywhere in the driving connections an apparatus familiar in the arts, like that, for instance, used on some machinetools and in some forms of sewing-machines; but as in the present case the variation in angular Velocity must be adjustable at Will while thespindles and wheelsarerevolving,amethod of accomplishing the objet is shown in Figs. lO and 1l, Sheet 3, in which 59 and 60 are revolving shafts in the same line, shaft 59, carrying a disk (il, provided with a slot 62, in which runs a crank-pin 63 on the end of a short shaft 64, connected to shaft 60 by a universal joint 65 and supported at 66 in a balljoint bearing adjustable transversely in relation to the disk 6l by a slide 67, operated in any customary way-for instance, by a IIO IZB

screw provided with a hand-wheel (i8. The effect is that when the center of the shaft 64 is made to coincide with that of 59, the crank-pin 63 and attached parts not only make the same number of revolutions in a given time as the disk 61, but have the same angular velocity throughout each revolution.

7hen, however, shaft 64 is thrown to one side, so that the crank-pin travelsin the path shown by the dotted lines, Fig. 1l, the crankpin 63 will be moved quite rapidly when near the outer boundary of the disk in the position 63, Fig. 11, and quite slowly when in the opposite position (designated 69) near the center of the disk. Apparatus for varying the angular velocity is designated, as a whole, T, and so referred to in various combinations. An equivalent for the same, applicable to a vibrating point of comparison,is described in Section 29 and similarly designated T.

Section 19. Then an apparatus T for varying the angular velocity is employed, if the balance be swinging through a very'small arc at the time of comparison, the comparator-disk may be adjusted to run at a correspondingly Slow velocity across the plane of reference, and when the balance is swinging through long arcs in the same time the comparingpointmay by the use of the apparatus be given a greater velocity at the time of the observation. The apparatus T can be applied in Figs. 1 and 2, Sheet l, by simply lengthening out the spindle f of comparator-disk F and applying the apparatus between the arm J and case E, so that the variationin angular velocity will be made in a fixed relation to the comparing-point a and not modified by the means of securing angular adjustment S. In such case a bent arm should be extended upward from the arm J to carry an additional bearing for spindle f near the comparator-case 'E, when the two bearings will correspond to those on shafts 59 and GO in Fig. 10, Sheet 3. The apparatus T, for varying the angular velocity, canbe conveniently applied anywhere in the operating connections of the form of comparator shown in Figs. 6 and 7, Sheet 3, yet to be described, providing it be put between an angular adjusting apparatus S (Sec. 10) and such comparator. Then such apparatus T is used to transmit mot-ion to a comparator-di sk, the connecting-gearin g should be arranged to run at the same or a multiple of the speed of the disk, and in general the comparing-disk F should either make one full revolution for each double vibration of the balance or a number of revolutions in the same time. So, also, a comparing-point a may be on a balance making a number of vibrations during the double vibration ot the balance to be compared, so longin either case as the View is cut off by a cut-ott apparatus V, yet to be described, (Sec. 21,) at all times except when the comparison is being made.

,Section 20. Figs. G and 7, Sheet 3, show a modification of the comparator illustrated in Figs. 1 and 2, Sheet l, designed to overcome an objection to that form of comparator, duc to the fact that since the axis of the balance u and of the comparator-disk F do not coincide in Figs. 1 and 2 the velocity can only be the same at one point of the revolution of the comparator and approximately the same for very limited angles on either side of that point. In Figs. 6 and 7 the balance u to be tested is set in a movement B, of which the plates 7J b are shown, and the latter attached to the bottom of a circular holder D', which, as shown, is arranged with its bottom protruding eccentrically through the top of a circular comparatorcase E', and secured thereto by clips 206 or other suitable means. The holder D' is, however, provided outside of case E with a handle d2 and guides d4, so that such holder may be turned upside down and pushed into a drawer-opening', (the same as the holder D, Figs. .1 and 2, Sheet 1,) and the opening in drawer-case closed by an at' tached plate d5, when the operation in relation to such holder D and its attached watchmovcment B will be the saine generally as that for the drawer D, Figs. 1 and 2. The case E', Fig. 7, is attached to a hollow sleeve i', with which it may be revolved in a bearing in a boss on the frame J'. The holder D' is so set in the case E' that the axis of balance-wheel u is in line with that of the sleeve t'. ithin the sleeve t" runs a hollow spindle f of a comparator-disk F', which is provided with a comparing-point a, corresponding in size and in distance from the center with the screw o, forming the object-point on the balance u. The comparator-disk F also carries an arm 46, provided at the end with a mirror 47, set in the same axial plane as comparing-point ct, which mirrorreceives an image of the points of reference ct and o and transmits it to a central mirror m, also carried by the comparator-disk F', which retlects the image through the hollow spindle directly to an eye-piece in some cases, but generally upon a third mirror 49, where it is viewed by a magnifyingglass e in an eyepiece L. The several mirrors 47, m, and 49 may forni parts ot' a multiple magnifyingglass or ot a compound microscope. The sleeve f4 is operated by an attached bevelgear 52, operated by a second bevel-gear 53, the spindle 54 of which is to connectv to a regulated prime mover R, (Sec. 16,) running at the proper speed through angular adjustment apparatus S, (Sec. 10,) and apparatus for varying the angular velocity T, (Sec. 18,) as desired. As shown, spindle 54 has a bearing in a stationary sleeve 55, upon which is pivoted the arm J in which the sleeve t" of the comparator-case E' is journaled. The eye-piece L, with attached tube carrying mirror 49, is shown pivoted at 5G in an arm 57, 'attached to the arm J', the result being that the arm J maybe turned around the sleeve 55, so

that the case E' will carry the face of the watch-movement B up or down to make tests bezel up or "bezel down g or the case E,with

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sleeve t, may be swung around in eye 50 of frame J" to make tests pendent up, down, right or left. So, also, comparator-case F. 1n ay be partially revolved with sleeve t" in bearingboss 50 to secure angular adjustment of the object-point v to the comparing-point a, instead of using the angular adjustment apparatus S (Sec. l0) to bringthe comparing-point to the object-point. This method of adjustment by swinging the comparator-ease is not of general application as it will change the vertical positions of movement when spindle t" is horizontal, but the swinging comparatorcase is the equivalent of apparatus S when spindle t" is vertical on either plan shown in Figs. 6 and 7 or in Figs. l and 2. In either of the positions of the comparatorcase E', Figs. 6 and 7, the eye-piece L may be set at various angles by swinging it on pivot. In the operation of the apparatus shown in Figs. 6 and 7 the object-mirror47 revolves around the pendent movement and in full View of the balance when not obstructed by the watchmovement or other means, as explained hereinafter. The plane of reference is fixed near the center of the least obstructed space-for instance, as shown, between the balancebridge and the horn of the back plate of movement-and since the obj ect-mirror 47, carried by comparator-disk F', turns on an axis coincident with that of the balance the image in mirror 47 of the object -points a and v1J is 4 nearly stationary for a larger arc, and comparisons can be more readily and closely made than with the apparatus shown in Figs. l and 2. It is desirable, however, to limit the view to a portion of the revolution of the comparator-disk when the balance is moving in one direction and with nearly maxim um velocity. This is accomplished by means of a movable ring r, resting on a ledge in the comparator-case E', such ring being provided with a pendent apron r4, which intercepts or cuts off the view of the points of reference a and o, except through an arc r r2, where the pendent apron is cut away. The gap thus left may be adjusted by turning the ring r; but, as illustrated, the comparator-arms are supposed to be moving at the bottom from right to left, so thatthe object-mirror 47 contains a fair View of the balance as soon as it passes the balance bridge and follows it around to the plane of reference, supposed to be where the object-point u is shown in Fig. 6, and the end of the screen or apron r1 can be adjusted so that the view will be out off soon after passing this plane and before the velocity of the balance is reduced materially. This form of apparatus has many advantages; but there is an objection to the number of mir- 'rors necessarily employed, which absorb a great deal of light. The illumination is secured through an opening o2 by means of a lamp and condensing lens or mirror, as is found most convenient for use. The arm 46, carrying mirror 7, may be curved in the horizontal plane, so that its shadow will not interfere with the illumination at theinstant of observation. As before, tubes 7c and kare provided for the circulation of air at any temperature desired in making temperature adjustments.

Section 2l. Many modifications of these elaborate forms ot apparatus are available to perform a part of the several operations referred to, in some of which the comparingpoint makes a full revolution, as has been described, and in others has a vibrating movement, as if located on a standard balance. In the latter case, however, it is desirable that the comparison only be made with the balances moving in one direction to avoid confusion, and the means used to accomplish this are available even in connection with ordinary vibrating apparatus, and when applied overcome one of the principal difficulties in teach` ing operators to vibrate balances. No confusion occurs with the form of apparatus shown in Figs. 1 and 2, for the reason that the comparator makes a full revolution for a double vibration of the balance, and the object-mirror m receives an image of the balance only during motion in one direction and the view is cut off during the 'return movement, for the reason that the mirror is directed away from the balance. In Figs. 6 and 7 the balance would be in sight when not obstructed by the parts of the movement, were it not for the screen r shown, which cuts olf the view except in the vicinity of the plane of reference. It is proposed in all cases to provide equivalent means forcutting off the view during one vibration, so that the operator will only see the points of reference during the other vibration. A method of doing this when two balances are employed, which illustrates particularly the principle involved, is shown in Figs. 25, 26, and 27, Sheet l, in which, for instance, t is the standard balance provided,l as is customary, with a hair-spring, and u the balance to be adjusted to run with the standard balance by varying the length of the hairspring. Starting the balances together, so that contiguous screws are moving in the same direction, ordinarily if 'a run faster than t a screw on the same forming the object-point which is caused at Iirst to coincide with one on u, forming the comparing-point, would be at the left during a vibration in one direction and at the right during a vibration in the other. As all the movements are very quick, this causes the greatest confusion to beginners and some people never can learn to vibrate. By, however, providing a screen or cut-off, consisting of a plate V, plane or curved, which is automatically thrust in the line of sight during the vibration in one direction and removed so that the screws can be seen during the vibration in another direction, the difficulty is removed and less skillful operators may learn to vibrate balances. In the plan shown the plate V is curved and connected by a rigid arm with a pendulum 73 under the table timed to vibrate the same as the stand- IIO ard balance. A hook 74C on cut-off plate 72 may be made to engage with a iixed catch 75 to keep the plate V out of the way while fixing a balance in position; but after starting the balance the catch 7 5 may be released and the pendulum wili start its vibrations, when, if the operator is sufficiently skillful in making the start, the points of reference will only be seen when moving in one direction and the view cut o when moving in the other. The evidentobjection to this arrangement is the skill required to start the pendulum exactly right after first overcoming the difficulty of starting the two balances alike. The firstdifficulty is overcome by operating the cut-off plate V bya motor giving the required number of vibrations per minute through an apparatus S for producing angular adjustment, (Sec. 10,) by the use of which the phases Aof the movement of the cut-off can be made immediately to so correspond with those of the balances that the pointsof reference will only be seen when moving in one direction. Apparatus for this purpose will be hereinafter described (Sec. 29) in connection with an application of the same principle in comparing two pendulums or a pendulum and a balance.

Section 22. A pendulum may be rated for time, temperature, and barometer on the principle stated herein by vibrating it in connection with a standard pendulum or equivalent -in a case, room, or other inclosure, through which air may be circulated to give the desired temperature and pressure. In Figs. 28, 29, and 30, Sheet 6, U represents a case for thispurpose containing a standard pendulum and one to be observed, and provided with pipe connections la and k for circulating air. The case maybe enlarged to a room in which clock-movements complete may be set up, and

a standard pendulum ora disk or point moving synchronously with such pendulum be caused to vibrate opposite the pendulum of each movement. A face view of a standard pendulum W is shown in Fig. 2 and a side View in Fig. 29. Atthe rear of the standard pendulum lV is hung the pendulum X to be rated, which can be put in place and removed through a door in the rear of the case. rThe standard pendulum W is preferably provided with an opening through its center, as shown, in which is secured a comparing-point a, moving close to the ball of the pendulum X, and upon the latter a mark lv is to be made as an object-point. An image of the points of reference ct and o is formed in an object-mirror 87, secured to the standard pendulum, which mirror reflects the image upward to another mirror fm, set oppositethe center of motion, and the image therein is viewed through an eyepiece L, provided with a magnifying-glass e, as in other cases. A lamp for illumination is provided in the direction o. The rays are reliected and concentrated by a condensing-lens o on the points of reference. A pane of glass to observe the operations from the front is represented at SG. A thumb-piece S9, operating a rock-shaft carrying a bent wire S8, is used to start the two pendulums together. Evidently as the two pendulums vibrate an image of the comparing-point a and mark on pendulumor object-point c will be seen in eye-piece L, the point in focus on the same appearing stationary and points at a distance appear to be moving slightly in radial lines around the same, so that any variation in movements in the two can be readily detected, except that the point which is faster will be at the right of the other during the vibration in one direction and at the left during the other, introd ucing the same kind of confusion referred to in Section 2l with reference to vibrating balances. To obviate this difficulty a cut-off V is provided in the form of a disk attached to an arm swinging on an arbor 90, whichl also carriesa fork 9l,operating in connection with a pin 92 on the arm 93, carried by a spindle 94, receiving motion through a crutchrod 95 from the standard pendulum. 9G 96 are small weights, which act as would their equivalent, a small weight above the center, to counterpoise the cut-off disk and to shift the center of gravity, so that the cut-oV will remain in either direction when shifted by the pin and fork. The cut-off V is so adjusted in reference to the vertical and the Width of fork and other parts so proportioned that as the pendulum when moving to thel right passes mid-position the pin 92 will, as shown,en gage with the fork 91 and swing the cut-o opposite the point of suspensiomwhere it will re-main until the pendulum returning from the right has passed the center of its movement to the left, when the pin will again engage with the other side of the fork and shift the cut-off V back to the position shown by the full lines, where it will remain While the pendulum completes its movement to the left and passes its middle position in moving to the right. The effect is that the cut-off V is interposed in the line of sight between the piece L and mirror m, cutting off the view as the pendulum passes mid-position in one direction, but is swung away, leaving the view unobstructed as the pendulum passes the center in the other direction. The cut-off may be arranged to cut off the line of sight periodically either Where the same runs horizontally, as shown, or Where it runs vertically to the other mirror. An equivalent effect can also be produced when artificial illumination is used, as shown in this case and in Fig. l, by having cut-off plate V cut off the illuminating-beam, and thereby darken or in effect cut off the line of sight during the movement in one direction. A modification is shown in Figs. 3l and 32, same sheet, in which a disk V', mounted on an arbor 90, is given a tendency to move to the right by a train or other means represented by acord and weight 96, and an anchor 97, operated by crutch-rod 95 from the rod of the standard pendulum T, allows the wheel V to turn like TOO IIO

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an ordinary escape-wheel. rihis wheel V is provided with openings 00, so arranged in conneet-ion with intermediate spaces in the face of the wheel that the image in mirror m will be seen from eye-piece L as the pendulum moves in one direction and the view of such image be cut off as the pendulum moves in the other. The operation is on the same principle as described in relation to watches. The pendulums being started together, it will soon be seen whether pendulum X is vibrating faster or slower than W, and at normal temperature the height of the ballon X would be shifted to change the rate. By circulating hot and cold air through pipes 7c and 7c the rates at different temperatures may also be observed and devices for securing compensation of temperature (not shown) adjusted to correspond with the observations. Similarly, if the pendulum X be erected in connection with a movement and compared, adjustments for barometer may be made by changing the pressures of the air admitted at 7c or 7c at constant temperature. Evidently a balance shown in dotted lines at u, Fig. 29, Sheet G, may be rated by comparing it with the motion of the comparing-point a, or the balance may be the standard and the point a or equivalent be carried by the pendulum to be rated.

Section 23. A series of pendulums may, it desired, be hung in a large box or room and rated with comparing-points moved synchronously with a standard by an external force, which may also operate the cut-offs. Fig. 33, Sheet 6, shows an arrangement for this purpose. UL shows a corner of the room. 100 represents a shaft oper'ated by any regulated prime mover R, (Sec. 16,) and through a jack-in-the-box gearing or any angular adjustment apparatus S (Sec. 10) operates through driven wheel 109 and shaft 102, directl y or through bevel-gears, the crank-disk 103, which, by means of a connecting-rod 104, bell-crank 105, and jointed rod 106, operates the lower ends of dummy comparator-pendulums W "V, provided with comparing points a.. A connection 107 leads oft at right angles to 104 from the same or a similarly-set crank 103 and moves a rod 108, which carries cutoft' targets V V, which are moved in front of the comparing-points a as the comparatorpendulums \V W" swing in one direction and to one side as such points are swung in the other direction. This arrangement is designed forl direct comparison without the mirrors shown in Fig. 29, same sheet. If such mirrors be used, the disks V would simply be operated mechanically across-the line of sight in the position of V, Fig. 29, or at any point where the line of sight would be interrupted thereby-for instance, on a line between mirrors m and 87, or in this or other applications, so as to obstruct the illumination from mirror O or equivalent. rThis mechanism is intended to be operated in connection with the pendulums of ordinary clockmovements placed behind the dummy pendulums XV', and the comparator-point d of the particular dum my pendulum then in usewould on commencing the comparison be made to coincide with an object-point mark on the pendulum of the clock being compared by means of an angular adjustment apparatus S, the comparison made, the rate adjusted by the operator or an attendant, and another pendulum operated upon while the first is attaining a steady rate. A somewhat similar arrangement is shown in Fig. 34, Sheet 1,in which a rotary motion is given to a series of cut-offs or comparators from -a prime motor below upward through an angular adjustment apparatus S, shown in the jack-in-a-box form and provided with a rod 102, (to be connected at right angles to the position shown,) carried along the face of the cases, so that it can be operated at any point. Both comparators and cut-offs may be included in the apparatus as before. At 190, Fig. 34, a clockdial movement is shown operated by the comparator-gearing, which should indicate the same time as a standard clock. In this gure pendulums which may or may not be erected with clock-movements are shown arranged in different rooms, one of which may be used as a hot room and the other as a cold room, alternately, 7c being the air connections, as in other cases.

Section 24. To provide for testing clocks and, if desired, watches under different barometric conditions, the comparator-chamber may receive air with a plenum of pressure from a chamberkept under constant temperature by connection to the outlet of a blower M or M', Fig. S, Sheet 4; or the comparatorchambercan be arranged to receive a reduced pressure or partial vacuum by connection to the inlet of such a blower, each connection being` provided with a valve for automatically regulating the outflowin one case and the iniiow in the other. The valve first above referred to may operate on the principle of a check-valve loaded to the pressure desired, and the valve in the second case be provided with a weight tending to open it, but which will permit it to shut when the pressure is reduced below the point required. In such an apparatus the actual pressure will vary with the atmospheric pressure at the time; but this may be overcome by operating the valves referred to by a large aneroid barometer placed within the pressure-chamber. A

special arrangement for regulating the press- IOO IIO

ers M and M, is conducted through a pipe 230 to the port 214 of the chamber of the valve Il' the pressure from the blowers M and M', Fig. 8, is insufficient, another blower 210, Fig. 35, Sheet 7, may be employed to draw the air from the chamber O and deliver it to 214. 211 represents a suction -blower discharging into the air, which, through a suitable pipe, is arranged to produce suction in a port 213 of the same valve 222. This valve is so arranged that ports 213 and 214 are closed at the same time. 213 is opened into the chamber U3 by an upward movement of the valve, and 214 opened into the same chamber by adownward movement of the valve. 217 represents an aneroid barometer ot the multiple-diaphragm type, the internal vacuum being balanced by weights 21S, and in part, through an ad j listing-screw, by a spring 219. The barometer, as sh'own in out-line, operates the short arm of a lever 220, which, at thc end of the long arm, is articulated to connection 221` operating the valve 222. In operation, weights 21S and spring 219 may be adjusted so that the valve 222 will stand in mid-position at any desired pressure within the limits of the apparatus, (shown by a mercurial or other barometer 223 in same chamber,) when if the pressure in chamber U3 rises the diaph ragms of barometer 217 will be compressed, thereby raisingl valve 222 and putting the chamber in communication with the suctionblower 211,so that the excess of pressure will escape. .11', on the contrary, the pressure fall, the diaphragms of barometer 217 will not sustain the load imposed by weights 21S and spring 219 and the valve 222 will descend and air be admitted through port 214 t0 restore the normal pressure. It the blowersbe capable of producing a suction or pressure varying two inches from that ot` the atmosphere, comparisons may ordinarily be made in chamber U3, between the limits of about twentyeight to thirty-two inches of mercury, which is more than will customarily be required in practice. In order to insure a draft of air from the chamber O at all times, a certain amount of air is to be admitted to chamber U3 through a pipe 215 or equivalent, regulated by a cock, and a certain amount of air is also to be drawn out ot' chamberU3 through a pipe 216, also regulated by a cock, which pipe is carried to an extreme point in the chamber, so as to insure circulation, when evidently at all times, even when the barometer inside the case is setto exactly the same pressure as the air outside, the pipes 215 and 216 will produce circulation to maintain the temperature, for the automatic arrangement will require the blower 211 to draw out through pipe 216 and port 213 as much air at least as is forced in through 215. A very small barometer 217 may be used to cause the movements of the lever 220 or other con-w necting part to operate the valve 222 indimiliar mill-governorg7 or the lever 220 may touch electric points, so that the valve 222 will be operated by electricity, as in the mechanism shown in Fig. 9, Sheet 4, (Sec. 14.) So, also,a float 224 maybe placed in the short leg of a mercurial barometer 223, connected electrically to a battery to form a ground and, through an arm 225,touching one or the other of the adjustable contact-points 226 227, complete electric circuits through magnet-s, (substantially in the same way as the thermometer 24in Fig. 9, Sheet 4,) and thereby operate the valve 222, Fig. 35, in the same way that valve n3 is operated in Fig. 9; or the mechanism in Fig. t) may simply operate the clutches of a mill-governor, which through a screw or equivalent operates the valve 222 more gradually. For tests of pressure above the atmosphere evidently the blower 211 may be omitted and the discharge from port 2,13 be directly in the air, and for tests below the pressure ot the atmosphere only blower 211 is necessary, and air can be drawn through 214 from any source. One blower can evidently at ditterent times be arranged to produce either suction or pressure at thc point desired, or any form of pump may be used instead of either of the blowers described or shown in either of the figures. It is evident, also, that the blowers M and M', Fig. S, Sheet 4, may be omitted by connecting the pressure side of a single blower to bot-h the nozzles N2 and N3, the suction of such blower being connected with the external air.

Section 25. Parts of the several operations possible with the complete forms ot apparatus shown in Figs. 1 to G, inclusive, Sheets 1, 2, and 3, may be accomplished with special machines embodying such portions of the principles as are applicable to the operations desired to be performed.- Fgs.19,20, and 21, Sheet 4, represent poising apparatus,t being a standard balance, and a a balance ot' which the hair-spring is to be made the right length to cause the balance to vibrate with the standard. In Fig.2O a small collaron the statt ofthe standard-balance t carries through a bent arm a mirror m above a narrow bridge 110. Animage is made in this mirror ot the comparingpoint a, attached also to the standard balance, and of an object-point c on the balance u, which image is viewed through an eyepiece L, being magniiied by a lens e, which may be a prismatic lens, as shown, ii desired to bend the line of sight-to one side for convenience. rlhe standard balance in this case carries a pin 112, operating in connection with a fork on a lever 113, to vibrate a staff 114, provided at its upper end with an arm 115, carrying a screen or cut-oit V in the line of sight to mirror m; or, if the mirror be omitted and the points of reference be viewed directly, the cut-off may, as shown in dotted lines in Figs. 2O and 22, Sheet 4, be extended to V3, so as to move over the space between the balances and obstruct an opening in a cover-plate 116, through which the points of IIO 

